MaysWind
107 lines
2.9 KiB
Go
107 lines
2.9 KiB
Go
package uuid
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import (
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"sync/atomic"
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"time"
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"github.com/mayswind/ezbookkeeping/pkg/settings"
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)
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// Length and mask of all information in uuid
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const (
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internalUuidUnixTimeBits = 32
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internalUuidUnixTimeMask = (1 << internalUuidUnixTimeBits) - 1
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internalUuidTypeBits = 4
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internalUuidTypeMask = (1 << internalUuidTypeBits) - 1
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internalUuidServerIdBits = 8
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internalUuidServerIdMask = (1 << internalUuidServerIdBits) - 1
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internalUuidSeqIdBits = 19
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internalUuidSeqIdMask = (1 << internalUuidSeqIdBits) - 1
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seqNumberIdBits = 32
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seqNumberIdMask = (1 << seqNumberIdBits) - 1
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)
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// InternalUuidInfo represents a struct which has all information in uuid
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type InternalUuidInfo struct {
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UnixTime uint32
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UuidType uint8
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UuidServerId uint8
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SequentialId uint32
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}
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// InternalUuidGenerator represents internal bundled uuid generator
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type InternalUuidGenerator struct {
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uuidServerId uint8
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uuidSeqNumbers [1 << internalUuidTypeBits]uint64
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}
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// NewInternalUuidGenerator returns a new internal uuid generator
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func NewInternalUuidGenerator(config *settings.Config) (*InternalUuidGenerator, error) {
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generator := &InternalUuidGenerator{
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uuidServerId: config.UuidServerId,
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}
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return generator, nil
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}
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// GenerateUuid returns a new uuid
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func (u *InternalUuidGenerator) GenerateUuid(idType UuidType) int64 {
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// 63bits = unixTime(32bits) + uuidType(4bits) + uuidServerId(8bits) + sequentialNumber(19bits)
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var unixTime uint64
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var newSeqId uint64
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uuidType := uint8(idType)
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for {
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unixTime = uint64(time.Now().Unix())
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newSeqId = atomic.AddUint64(&u.uuidSeqNumbers[uuidType], 1)
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if newSeqId>>seqNumberIdBits == unixTime {
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break
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}
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currentSeqId := newSeqId
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newSeqId = unixTime << seqNumberIdBits
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if atomic.CompareAndSwapUint64(&u.uuidSeqNumbers[uuidType], currentSeqId, newSeqId) {
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break
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}
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}
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seqId := newSeqId & seqNumberIdMask
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unixTimePart := (int64(unixTime) & internalUuidUnixTimeMask) << (internalUuidTypeBits + internalUuidServerIdBits + internalUuidSeqIdBits)
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uuidTypePart := (int64(uuidType) & internalUuidTypeMask) << (internalUuidServerIdBits + internalUuidSeqIdBits)
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uuidServerIdPart := (int64(u.uuidServerId) & internalUuidServerIdMask) << internalUuidSeqIdBits
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seqIdPart := int64(seqId) & internalUuidSeqIdMask
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uuid := unixTimePart | uuidTypePart | uuidServerIdPart | seqIdPart
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return uuid
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}
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// ParseUuidInfo returns a info struct which contains all information in uuid
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func (u *InternalUuidGenerator) ParseUuidInfo(uuid int64) *InternalUuidInfo {
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seqId := uint32(uuid & internalUuidSeqIdMask)
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uuid = uuid >> internalUuidSeqIdBits
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uuidServerId := uint8(uuid & internalUuidServerIdMask)
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uuid = uuid >> internalUuidServerIdBits
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uuidType := uint8(uuid & internalUuidTypeMask)
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uuid = uuid >> internalUuidTypeBits
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unixTime := uint32(uuid & internalUuidUnixTimeMask)
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return &InternalUuidInfo{
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UnixTime: unixTime,
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UuidType: uuidType,
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UuidServerId: uuidServerId,
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SequentialId: seqId,
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}
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}
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